Home – Home – Jornals – Earth’s Cryosphere 2024 number 3

The structure of the upper part of permafrost and the topographic features in the northeast of Western Siberia were shaped by changes in the natural environment in the Late Pleistocene and Holocene. In 2016-2021, sections of different landforms - ridges and thermokarst-erosional hollows - were studied within the third lacustrine-alluvial plain of the Pur-Taz interfluve. The upper part of the plain includes the Kargin-Sartan alluvial, lacustrine, and slope sediments and Holocene peatlands. Based on the stratigraphy and new geochronological data on the Pur-Taz interfluve, the consequences of the activation of neotectonic processes in the Sartan period and the influence of climatic factors on the differentiation of accumulative and denudation processes in the Holocene were identified.

This study is aimed at a preliminary analysis of ground temperature data from ten thermometric boreholes drilled and equipped by the authors in the Upper Kolyma Highland (Magadan region) in 2021-2022. The boreholes of up to 15 m in depth are located in characteristic landscapes (rocky talus, mountainous tundra, larch woodland, river valleys) of the highland at heights from 618 to 1182 m asl. Continuous monitoring of ground temperatures with a time step of 4 h was carried out. Data on the mean annual rock temperatures, seasonal thawing/freezing depths, and the depths of zero annual amplitude were obtained. The mean annual ground temperature varied from -0.1 to -3.8 °C. The depth of seasonal thawing ranged from 0.9 to 2.6 m. The depth of zero annual amplitudes was 11.5 and 13 m in two boreholes. Two boreholes located in talik zones recorded freezing depths of 2.6 and 3.6 m. Ground temperature regimes within the same region differed significantly depending on landscape conditions: elevation, landform, composition of the rock, character of vegetation, and other factors. Based on the data obtained, it is planned to further develop the geocryological monitoring network in the Magadan region. For some of the boreholes, a full annual cycle of observations on ground and air temperatures, precipitation, and snow cover depth is available. As information on the state of permafrost in the territory under consideration is virtually absent, publication of the obtained data of relatively short-term observations is relevant and timely.

A new model of pure water freezing potential (Workman-Reynolds potential) explained the positive electric charge of ice relative to water during crystallization by the fact that protons were captured faster than hydroxide ions by numerous traps of charge in ice - interstitials. In the present article, additions have been made to this model to extend its application from pure water to aqueous solutions with an impurity concentration in the parent solution of 10^-4 mol/L or more. The additions take into account the ability of impurity anions and cations to act as acceptors for protons and hydroxide ions in ice. As a result of capture by acceptors, the equilibrium concentrations of protons and hydroxide ions can shift significantly in favor of the former or the latter. This shift should radically affect the kinetics of filling the charge traps (interstitials) with protons or hydroxide ions and the sign of the electric charge of ice relative to the solution. In particular, the model explains the negative ice charge during crystallization of 10^-4 mol/L KCl solutions.

Based on observation data on typical areas of the Prioksko-Terrasny Reserve for 1999-2021, the influence of snow accumulation on the dynamics of the groundwater level was clarified with due account for the variability in air temperature and precipitation. An assessment of the spatial heterogeneity of seasonal and long-term variability in meteorological characteristics and the groundwater level was made. A regression analysis demonstrated that the snow storage has a significant influence on the long-term dynamics of the groundwater level during both the snowy season (December-April) and the maximum rise of the groundwater level (May-July). The effects of the air temperature of the cold season, duration of thaws, and the accumulated positive air temperatures during them on the groundwater level were statistically insignificant. The obtained conclusions complement the results of studies of the relationship between the variability of snow cover characteristics and the depth of groundwater under the conditions of modern meteorological regime and can be used to specify regional features of water exchange processes.

Experimental and numerical modeling of the temperature regime and the deformed state of the highway structure, which is a geotechnical system of “subgrade and the foundation of the highway made of frozen soil”, was carried out. Potential disturbances of the temperature regime are considered, and a design and technological solution for thermal stabilization of the soil foundation under the subgrade in flooded areas is proposed. It implies the use of geocontainers. To study and evaluate the temperature regime of the highway structure, a series of laboratory experiments were carried out. To take into account the viscoelastic properties of the soil in the mathematical model of the soil foundation, time functions of the relative settling of the soil foundation with geocontainers in the chosen temperature regime were obtained.

The proposed calculation takes into account the peculiarities of the operation of the heat pump as part of the surface foundation on permafrost soils, i.e., the heat flow from the heating circuit of the pump to the cooling circuit. Heat transfer reduces the conversion coefficient of low-potential heat into high-potential heat, but, unfortunately, this is ignored in well-known publications. In addition, the calculation shows a significant effect of the freon brand in the evaporation-condensation circuit of the refrigeration machine on the conversion coefficient.

Igor Emelyanovich Guryanov, Candidate of Technical Sciences, passed away on February 3, 2024, after a long battle with a serious illness. A renowned expert in the field of foundation engineering and frozen soil mechanics, he worked at the Melnikov Permafrost Institute for many years. He developed a new field in geocryology - engineering cryolithology - and authored two fundamental monographs on this very promising topic. He was a member of the International Society for Soil Mechanics and Geotechnical Engineering.